Jeff Gordon will fill in for Dale Earnhardt Jr. for the next 2 NASCAR races

Dale Earnhardt will sit out at least the next two NASCAR races as he continues to experience concussion-like symptoms, Hendrick Motorsports announced Wednesday.

Earnhardt was sidelined for last week’s race at New Hampshire Motor Speedway, and will miss Sunday’s event at Indianapolis Motor Speedway and July 31 at Pocono Raceway. Jeff Gordon will come out of retirement to drive the No. 88 car until Earnhardt returns. No timetable on Earnhardt’s exact return is known.

Earnhardt said in a podcast recorded Sunday night that his mind “feels sharp,” but that he is having issues with balance and nausea and will take his recovery slowly. NASCAR’s most popular driver for a record-tying 13 consecutive years is no stranger to head injuries, having sustained a concussion in 2002 and two in 2012 that occurred six weeks apart, which caused him to miss two races.

Earnhardt’s latest setback is believed to have resulted from crashes July 12 at Michigan International Speedway and July 2 at Daytona International Speedway. After the Daytona race, he said he began feeling ill and thought he might have either a sinus infection or allergies, and competed July 9 at Kentucky Speedway before seeking medical consultation where he was then advised to not race.

In a statement, Hendrick Motorsports said Earnhardt underwent further evaluation at the University of Pittsburgh Medical Center Sports Medicine Concussion Program on Tuesday. He will not travel to Indianapolis or Pocono.

“Our focus is giving Dale all the time he needs to recover,” team owner Rick Hendrick said. “There’s nothing we want more than to see him back in the race car, but we’ll continue to listen to the doctors and follow their lead. What’s best for Dale is what’s best for Hendrick Motorsports and everyone involved with the team. We’re all proud of him and looking forward to having him racing soon.”

Gordon, 44, won four championships and 93 races in a career that spanned from 1993-2015 before retiring last season, and his return comes at a track where he’s had much success. Gordon, who grew up in nearby Pittsboro, Ind., led all NASCAR drivers in wins, top-five and top-10 finishes, and laps led at Indianapolis.

“Jeff’s a team player,” Hendrick said. “I know he’ll be ready, and I know Dale has incredible trust in him. It’s going to be an emotional weekend (at Indianapolis) with Dale not being there and seeing Jeff back behind the wheel.”